Aids is a virus that originated within the homosexual group. The first origin of HIV is debated, however one of the most common theories suggests that HIV began in the Congo, when a homosexual man has bestality sex with a primate (baboon) which carried SIV (similar to the human form: HIV).
This theory is debated, however I personally believe it. There are many solid and factual studies that support this theory.
I think the answer is intensity
Yes, your heart does not need to pump as hard so your blood pressure is lower.
Lifting a weight 10 times is a kind of ISOTONIC contraction. Holding a heavy machine part steady while securing it in place may be categorized as ISOMETRIC contraction. Lifting heavy cans and putting them on a shelf may be called an ISOTONIC contraction. Flexing your leg muscles and holding the flex is an ISOMETRIC contraction. Lifting your heavy book bag several times is good ISOTONIC contraction.
